Process of treating mineral substances by heat and pressure.



No. 7|2,so7. Patented Nov. 4, I902. v. KARAVODINE.

PROCESS OF TREATING MINERAL SUBSTANCES BY HEAT AND PRESSURE.

(Application filed Mar. 27, 1900.)

(No Model.)

W11" asses awmbmx To all whom it may concern:

- UNITED STATES ATENT OFFICE.

VICTOR KARAVODINE, or PARIS, FRANCE.

PROCESS OF TREATING.MlNERALSlJBSTANCES BY HEAT AND PRESSURE.

SEZEGIEIGATION formingpart of Letters :Patent 0. 712,807, dated November 4, 1902- Application filed March 27, 1e00, Serial No. 10,380. (No specimens.)

Be itknown that I, VICTOR KARAVODINE,

engineer, asubject of the Emperor of Russia,

residing in Paris, in the Republic of France, (whose postal address is 28 Rue Lacordaire, Paris,) have invented a certain new and useful Process of Treating Mineral Substances by Heat and Pressure, of which the follow ing is a specification.

.-My invention has for its object an impro ved process for converting into solid masses sub+ stances which contain water chemically combined-such, forinstance, as the water of constitution or crystallization. Thismethod consists in subjecting the said substances simul taneously to a high temperature and a strong compression in such a way that thewater is expelled by the high temperature, while the compressionagglomerates the molecules and causes them to adhere together. The water being thus expelled, solid substances result having the same qualitiesas',for instance,the hydrates of aluminium (Al O 3H O) or of silicon, (SiO 2H O,) the alkaline earthy hydrates, such as lime, (oan,o,,. magnesia, (MgH O,) iron, (2Fe O,3H O,) or, copper, (OuH O,) and their analogues, the latter being taken separately or intermixed or mixed with fibrous and pulverulent substances. .All like combinations which contain the water of constitution and ofcrystallization (but not merelyhygroscopic water)being subjected tola hot compression,that is to say, a compression during which the body subjected to thepresjsure is heated yield masses so hard and sov solid that it has hitherto been impossible to obtain similar substances by means of the saturation of fibrous bodies with salts and reagents producing the hereinbefore mentioned hydrates in the pores of the fibrous body. The insufficient solidity of masses ob- Q tained. by meansof the second-named proc- (ans arises fromihefact that the hydrates in drying greatly diminish in volume, (from ten to twenty,times,) being convertedinto anhydrids or into hydrates with a small quantity of water,and this is why they assume a sandy appearance, leaving in the masslarge pores, and are deficient in solidity. On the contrary, in the method which I propose the hy; drates(or in general the compounds containing water of constitution or crystallization) and a mixture of them with pulverized and fibrous substances are placed in a metal mold and subjected to hot compression, the mass being compressed by means of a hydraulic press and the metallic mold being heated at the same time by any suitable means. Owing to this hot compression the Water of constitution. or of crystallization (or both together) evaporates from the hydrates and escapes through i the interstices of the mold, and the molecules of the anhydrids or of the hydrates with a small quantity of water are united owing to the pressure in proportion as the water escapes and adhere together at the very instant when they are freed from the water, and'this is the reason why the volume of the mass becomes much smaller than before the heating and obtains a much greater solidity. Forinstance, if I take one kilogram of asbestos and mix it with one kilogram of silicate of soda, (K,Si,0,,) at 36 Ban m and add to this mixture .36 of alum, preferably am moniaoal alum, (NH,) Al SO,2et

(H O-,) I obtain a gelatinous mixture in which the asbestos fibers are surrounded with silicate of aluminium [(Al O (SiO (H O) Then this paste,-which is preferably freed from the foreign salts by washing and from the superfluous water which itcontains by means of a slight pressure, is subjected to a hot compression in a metal mold. The mold 'must be heated to from 250 to 400 centigrade at the same time as the substances which are therein contained are compressed. --There is thus finally obtained a veryhard elastic and easily-polished mass which is a bad conductor of electricity, especially if it be saturated with boiled oil or colophony melted with. one to three parts of a suitable resin. The less asbestos there is in this paste in proportion to the hydrates the harderwill be the mass and the less elastic, and it willhave the appearance of stone. l

. Instead of silicates or aluminium hydrate of silicon may also be obtainedby pressing ithotin'the manner just described. With this object hydrate of silicon is first precipitated for instance, in a mixture of asbestos and silicate of soda in the proportions of one part of asbestos and one part of silicate of soda by chemical meansfor instance, by the use of carbonic acid. Hydrate of aluminium may also be obtained by mixing the asbestos with a saturated solution of alum and then treating this paste by means of ammonia, (NH,,.) The operation may also be performed by adding to the mixture of asbestos and silicate of soda a solution of any suitable alkaline earthy salt-for instance, calcium or magnesium in the form of a chloric compound, (CaCl MgOl and there will be obtained in the fibers of the asbestos hydrated silicate of calcium (SiOaO +aqua) or of magnesium, (SiMgfi-aqua). If in this case instead of silicate of soda a suitable solution of an aluminiumsalt be taken, there will be obtained hydrate of aluminium of the alkaline earthy metal-for instance, (Al CaO aqua or Al MgO +aqua.) Asbestos with hydrate of iron, or wolfram, (I-I WO,+aqua,) or copper, or the like yield under the same conditions very hard and very solid masses. The hydrate of silicate of calcium or magnesium or the aluminates of these metals mixed with caustic lime (CaHO or with magnesia (MgHO or without these latter also yield a very solid whitish mass. Instead of asbestos another suitable material-such, for instance, as graphitemay be employed, and the mass obtained (always by means of hot compression) will be of great solidity and may be employed for the manufacture of crucibles, penoils, crayons, carbons for electric lamps, and

the like.

The hydrates in question may be prepared separately and freed from superfluous water by means of a light pressure and mixed with fibrous and pulverized substances in the proportion of one part of such substances and one part of hydrate. These hydrates may also be preliminarily dried at a low temperature of from to centigrade and subjected to a hot compression alone or with fibrous and pulverized substances and damp or dry. The mixtures will then in all cases have the same solidity.. The mass composed of gelatinous hydrates may also be preliminarily moistened and dried at a temperature not exceeding 50 centigrade and be subjected, damp or dry, to a hot compression. It is possible to obtain, for instance, an asbestos mass by mixing it with natural hydrates-such, for instance, as tripoli or silicions fossil meal (hydrate of silicon) or with elaywhich mass by means of hot compression also becomes resistantand solid. These masses become still more solid if to the tripoli there be added one to three per cent. of caustic lime (KOH) and to the clay a like quantity of some suitable acid.

In all the masses otwhich mention has been hereinbefore made the quantity of the hydrates and of the fibrous and pulverized bodies may be modified indefinitely, because even a small quantity of a suitable hydrate say two to five per cent. mixed with the said bodies yields by means of hot compression a solid product, and, vice versa, by diminishing simultaneously the quantity of the fibrous and pulverized substances a mass will be obriaso'r tained in which these substances are entirely absent, because hydrates alone similarly to all the other chemical compounds containing water of constitution and crystallization, or mixed with one another yield by means of hot compression very hard masses in the form of minerals. In order that these minerals shall not adhere to the walls 'of the mold, they may after being compressed without being heated be placed in another larger mold and the interstices filled with graphite or talc and then subjected to a hot compression. Under these circumstances the hydrates are compressed by the pressure of soft bodies (graphite or talc.)

Referring to the accompanying drawings, showing an example of an apparatus intended to carry out my invention, Figure 1 is a vertical section through the apparatus. Fig. 2 is a horizontal section on the line at a: of Fig. 1.

A and B are the upper and under plates of a hydraulic press.

a represents sheets of asbestos board for preventing heat from being transmitted to the plates, and O, O, and O are metal plates interposed between the plates of the press and the mold in which the substances are heated and compressed.

The substance M to be compressed and heated is inclosed in a mold-D, formed of two semicircular pieces, as shown in Fig. 2. The external surface of the steel mold D is slightly tapered, and it is surrounded by the steel ring E, having its internal surface also slightly tapered.

F represents a compressing-piston, J a metallic casing lined internally with asbestos, as an insulating material which also resists a high temperature, and O and P represent the admission and discharge pipes, respectively, for the hot gases coming from a suitable furnace, while instead of hot gases for certain material molten lead may be employed.

My process is applied in the following manner: The substance to be compressed is introduced into the matrix D, and the piston F is inserted in the upper end of the mold, and after the ring E and the casing J have been fitted on the two plates 'of the press are approached in such a way as to hold the apparatus. Then the hot gases are caused to cir culate around the ring E at the same time that pressure is applied by means of the press. Account may be taken of the temperature by observing the color of the ring E, which is of steel and which assumes tints corresponding to the degrees of temperature. As the piston is not hermetically fitted in the matrix D and also the two parts of the matrix D are not drawn together in an absolutely tight manner, the water expelled by the heat is discharged through the interstices, while at the same time the molecules are agglomerated by the compression.

As regards the degree of temperature necessary for heating the mold during the compressionit must be noted that the higher the temperature;the'harderwill be the mass, except of course in the cases Where bodies which decomposeat too high a temperaturesuch, forinstance, as paper-pulp, which cannot endure a temperature higher than 150 to 200 centigrade-are mixed. with vthe'hyd'rates or 1 order to facilitate the operation the said mass may be inserted between two metal plates 'andthe whole passed between hot cylinders,

andin order thatthemass shall not adhere to thesaid plates they may be powdered with talcor covered with paper or asbestos paper.

" I declarethat whatgl claim is .1. The processotitreating mineral substances insoluble in.water and containing water chemically combined to produce refrac- 'tory solid compact unasses, which process consists in subjecting said substances simultaneously to atemperature of from 250.t0

400 centigrade, and to ahigh pressure exceeding one hundred kilograms ,per square centimeter, thereby expelling byheat the chemically-combined water, and agglomerating the molecules by pressure, substantially as described.

2. 'The process of treating mineral substances insoluble in water and containing water chemically combined to produce solid, compact masses, which process consists in mixing fibrous substances with the said mineral substances, and subjecting the combined mass simultaneously to a temperature of from 250 to 400 centigrade and to a high pressure'exceeding one hundred kilograms per square centimeter, substantially as described.

3. The process of treating mineral substances insoluble in water and containing water chemically'combined to produce solid, compact masses, which process consists in mixing pulverulent substances with said chemical substances, and then subjecting the combined mass to a temperature of from 250 to 400 centigrade and to a high pressure exceeding one hundred, kilograms persquare centimeter, substantially as described.

In witnesswhereof Ihave hereunto signed my name, this ]4:th;day of March, 1900, in the presence of two subscribing witnesses.

- VICTOR KARAVODINE' Witnesses:

v Auousrn FO INoL, Vtoron DEMARENDOWSKI. 

